The invention refers to an electric motor, especially to a small-size motor, adapted to drive at least one wiper arm of a windshield wiping system of a motor vehicle, with a rotatably mounted armature spindle, wherein one of the spindle ends is axially acted upon by means of a spring loaded prestressing member. The spring has the form of a spring winding with one spring leg retained by a housing, while the other spring leg is connected with the prestressing member which is rotatably mounted in this housing.
An electric motor of this type is known from the German specification DE-OS 20 52 541 which provides a prestressing member having an adjusting screw, the inner end of which abuts directly on the driving shaft of the motor and which is loaded by means of the spring in the tightening direction. Due to the advancement of the adjusting screw, there is no axial play. Because the screw may play in the internal screw thread, an impeded motion results which can be compensated only by a strong spring.